Saquinavir is a new drug which works in a different way from another group of anti-HIV drugs, the reverse transcriptase inhibitors (including AZT, ddC, ddI and d4T). Saquinavir interferes with virus production by inhibiting an enzyme "proteinase" which is needed by HIV to form viral proteins. The CD4 cell, also known as the T helper cell, is the critical cell in the immune system and is a major target of HIV. There are two forms of this investigational drug. The first is Saquinavir which comes in a hard gel capsule, the second and new is SQV-SGC which comes in a soft gel capsule. The purpose of this study is to compare the activity against HIV, safety, and pharmacokinetics of SQV (hard gel capsule) 600 mg, to SQV-SGC (soft gel capsule) 400 mg, 800 mg and 1200 mg given by mouth every 8 hours for 4 weeks.